The present invention relates generally to improvements in internal combustion engines and it relates more particularly to an improved connecting rod between the engine piston and crank shaft.
In the conventional multipiston type internal combustion engine the pistons are coupled to a crank shaft by connecting rods to translate the reciprocating motion of the pistons to the rotary motion of the crank shaft. This mechanism contributes greatly to a drop in engine efficiency and to frequently excessive vibration particularly in high speed engines and a good part of this is due to the weight of the connecting rod. The connecting rod is subjected to great variations in stress, rapid periodic changes between compression and tension, torsion and high periodic shock, and must not only be constructed to withstand such changing and high stresses which frequently lead to fatigue failures but must be properly balanced both statistically and dynamically.
The conventional internal combustion engine connecting rod consists of a main column provided at one end with a bearing collar for engaging the piston pin and at the other end with a split bearing collar for engaging a crank shaft eccentric pin. The section of the split collar is formed at the end of the column and the other section of the split collar is separably bolted to the first section by a pair of side bolts engaging aligned smooth and tapped bores in enlarged side portions of the collar. The high stresses imparted to the connecting rod are transmitted to these enlarged sections as well as to the connecting bolts necessitating the use of heavy bolts and greatly enlarged side sections thereby contributing to the great weight of the connecting rod which is commonly made of forged or cast steel. Producing the connecting rods of aluminum or other light weight metal does not appreciably alleviate the weight problems since a greater volume of metal is required particularly at the split ring coupling areas and leads to other disadvantages.
It is a principal object of the present invention to provide an improved reciprocating piston type engine.
Another object of the present invention is to provide an improved reciprocating piston type of internal combustion engine particularly of the multicylinder high speed type.
Still another object of the present invention is to provide an improved piston crankshaft coupling connecting rod.
A further object of the present invention is to provide an improved connecting rod which is of high strength and high shock and fatigue resistance and of low weight whereby to minimize engine vibration even at high speeds.
Still a further object of the present invention is to provide a connecting rod of the above nature characterized by its low cost, ease of fabrication, long effective life and high versatility and adaptability with a resulting improvement in the efficiency and performance of the engine.
The above and other objects of the present invention will become apparent from a reading of the following description taken in conjunction with the accompanying drawings which illustrate preferred embodiments thereof.
In a sense, the present invention contemplates the provision of an improved connecting rod for coupling an engine reciprocating piston to a crank shaft, the connecting rod comprising a column, a first bearing collar located at one end of the column engaging a piston pin, a split second bearing collar at the opposite end for engaging an eccentric pin on a crank shaft and including opposite inner and outer sections, said outer section being separable from said inner section and an elongated flexible securing member engaging the outer periphery of the collar outer section and a surface of at least another portion of the connecting rod to firmly secure the split collar outer section to the split collar inner section. Advantageously, the securing member comprises a high strength flexible metal band, the ends of which are longitudinally adjustably joined to permit the tightening or loosening of the securement of the split collar outer section and in its preferred form the ends of the metal band are provided with loops which engage coupling pins carried by respectively internally threaded and smooth bored blocks which engage a bolt so that turning the bolt in one direction draws the band ends together and in the other direction separates them.
In accordance with one preferred embodiment of the present invention, the split bearing collar inner section is integrally formed at the end of the column and the securing band encircles and tightly engages the peripheral surface of the first and second collar sections, the ends of the bands being longitudinally slotted and looped to engage the respective coupling pins and to clear the column. In a modified form the sides of the column are tangent to and extend from the sides of the split collar inner section and the band encircles the split collar outer section, the column and the opposite bearing collar and the band end coupling member registers with a recess formed in the column. According to a further embodiment the lower end of the column is provided with transverse passageway and terminates in an arcuate saddle which engages the split collar inner section. The split collar sections and column are releaseably locked in assembled condition by a flexible band which extends about the periphery of the split collar lower section, the cradle and the upper section and the ends of the band are connected by the adjustable coupling member which registers with the passageway.
The use of the flexible securing member or band for retaining the split bearing collar in a locked assembled condition overcomes the drawbacks and disadvantages of the conventional connecting rod structures. The flexible band is lightweight, strong and adaptable, and not only reliably locks the split collar in an optimum closed condition but contributes to the overall strength and shock and fatigue resistance of the connecting rod as well as that of the bearing collars. The mass of the connecting rod structure is greatly reduced, thereby contributing to increased engine efficiency and improved low vibration performance even at high speeds. Furthermore, the present improved structure permits the use of a wide range of desirable materials, in addition to forged or cast steel, stamped metal may be employed as well as the light weight metals such as aluminum, magnesium, titanium and alloys therefor as well as the high temperature synthetic polymeric compositions which may be fiber reinforced by compositions of carbon fibers and other high strength fibers.